Payment for tracking device of writen off car.

I bought a car in 2010 and installed tracking device. The car was written off. I bought another vehicle at the end of 2011 and installed another tracker. A year later I received calls demanding that I continue paying for the device that was installed in the car that was written off. I refused and asked why they did not continue with that contract that was linked to the previous car. TRACKER is unfair to me as their client and did not work in good faith. I'm never doing business with them again and adviser other motorists to be careful when dealing with them in the future.